Comparisons of age, food intake, body weight and body composition at the onset of sexual maturity were made between dwarf and normal chickens from lines selected for high or low juvenile body weight. At the same age birds which had started to lay were significantly heavier and contained significantly more abdominal and carcass fat than those which were not laying. Differences between normal and dwarf pullets within lines varied with genetic background, indicating differences between lines in meeting a body weight or a body composition requirement, or both, for the onset of sexual maturity.

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The influence of two management factors on the incidence and severity of leg abnormalities was studied in three experiments utilizing a total of 7200 male broiler chickens. Birds provided intermittent illumination (IL) had significantly fewer and less severe leg abnormalities than birds under continuous illumination. Broilers given 2.94 cm of feeding space per bird had more but less severe leg defects than birds given 1.47 cm of feeding space. Bird activity was greater under IL and is deemed to be at least partially responsible for the stronger legs recorded among broilers under this management practice.

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